Also, it is not certain that enantiornithines had triosseal canals, since no fossil preserves this feature.

Several fossils preserve the outline of individuals and show that they were robustly built, with a thick tail and legs.

Furthermore, as fossils do not preserve behavior or muscle, it can be difficult to discriminate between a poor flyer and a good glider.

The fossils are numerous, but also very well preserved.

The fossil has preserved just nine tail vertebrae; likely fifty or more had been originally present.

The fossil preserves no traces of any skin, scales or feathers.

Most fossils preserve only the hard parts of organisms, e.g. shells.

The fossils in the Wilderness preserve a record of freshwater life in and on the edge of the great delta at that time.

Some fossils preserve original features in exquisite detail, while others are much cruder remnants.

The rocks and fossils preserve evidence of ancient ecosystems and give scientists clues about how early mammal species lived.